feat: PEP 723: running scripts with inline metadata

[frostming]

Signed-off-by: Frost Ming me@frostming.com

Pull Request Checklist

• A news fragment is added in news/ describing what is new.
• Test cases added for changed code.

Describe what you have changed in this PR.

[codecov]

Codecov Report

Attention: Patch coverage is 87.09677% with 8 lines in your changes missing coverage. Please review.

Project coverage is 85.32%. Comparing base (4a8cb63) to head (5afae7f).
Report is 99 commits behind head on main.

Files with missing lines	Patch %	Lines
src/pdm/cli/commands/run.py	90.56%	2 Missing and 3 partials ⚠️
src/pdm/cli/commands/venv/backends.py	66.66%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2924      +/-   ##
==========================================
- Coverage   85.32%   85.32%   -0.01%     
==========================================
  Files         106      106              
  Lines       10630    10676      +46     
  Branches     2314     2326      +12     
==========================================
+ Hits         9070     9109      +39     
- Misses       1091     1094       +3     
- Partials      469      473       +4     

Flag	Coverage Δ
unittests	85.09% <85.48%> (-0.02%)	⬇️

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